Caroline Champenois

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Ion clouds in a linear Paul trap

Here is the picture of an ion cloud emitting laser induced fluorescence. It is made of several tens of thousands of calcium ions, laser cooled and trapped in a linear Paul trap. The elliptic shape is the signature of a correlated phase (liquid or crystal) whereas the layers which can be seen on the cloud demonstrate a local self-organization in a Coulomb crystal where the radio-frequency electric field is minimal, around the symmetry axis of the trap.

A three photon dark resonance

A coherent population trapping involving three (optical) photons identified in ions belonging to the same family as Calcium ions is demonstrated in a cloud of trapped Ca+. The dark line observed in the fluorescence of the cloud is referenced to a transition et 1.8 THz.

High Precision Physics using an Optical Fibre Link and Optical Frequency Combs, Les Houches, 22-26 april 2019

After more than 15 years of development, optical fiber links and optical frequency combs are now sufficiently mature to be spread and shared outside the time/frequency metrological institutes. The school follows on from the international development of optical fiber links and its objective is thus to broadcast among a wide community of physicist the possibilities of high precision measurement thanks to the optical fiber transfer of an optical frequency reference, coupled to a frequency comb.